Show that Newton's first law of motion is contained in second law ?
Newton’s first law tells that the body’s state of motion or rest is unchanged until and unless it is acted upon by some external force. The second law tells us about the change in the state of motion or rest when a force (external force) is applied on the body.
So, second law contains the first law as it tells us what will happen to the state of the body when force is applied on it.
As we know that
F=ma (here a can be written as v-u/t)
F=m(v-u)/t
Ft=v-u (according to the first law F =0)
0=v-u
-v=-u
v=u
Therefore first law can be derived from the second law.